A telecommunications device, for example, a telecommunications aggregation element such as a DSLAM (Digital Subscriber Line Access Module), typically has multiple line card slots that receive a number of DSL (Digital Subscriber Line) modems each typically formed as a separate line card. When only a portion of the card slots have modems, the device is not fully populated. The amount of electrical power required by the device is approximately proportional to the number of modems installed in the device. Conventional fault protection systems are used with such devices to reduce excess currents that may damage components in the device. These conventional fault protection systems typically include one or more circuit breakers having a trip point (a disconnect current value) that is chosen based on the device being fully populated with modems and other circuit devices.
Such conventional protection systems using circuit breakers typically have not worked well if the telecommunications device is partially populated with modems, and in particular, if there are a smaller number of slots populated with modems or similar line cards. For example, if a device has slots for 22 line cards, but there are only two installed line cards, then the power requirements for this device configuration is approximately 10% of the fully populated device. Because all line cards do not have the same power requirements, however, this 10% value represents a typical value. There is thus a need to have a protection circuit and system that works in conjunction with such telecommunications devices and capable of meeting the protection requirements for such telecommunications devices no matter the number of any installed line cards.
It should also be understood that a telecommunications device, such as a DSLAM, typically has one or more access modules, for example, line cards. Each of the access modules has multiple xDSL chip sets, which use a large portion of their power that is supplied to the telecommunications device. Because of the rising cost of energy, the size and cost of a device's power supply and the size and cost of its cooling system are approximately proportional to the amount of power used by a chip set. It is desirable, therefore, to reduce the power used by the chip sets. This is even more understandable with the current societal trends to be more energy conscious. In general, service providers furnish a customer with a data rate equal to or greater than the data rate in a Service Level Agreement (SLA), and thus, there is room for improvement and energy savings.